Our hauler delivered a load of concrete sand in a truck that had previously hauled urea. We batched the sand in several truckloads of concrete used in the walls for a residential basement. When finishers placed the basement floor, they complained about a strong ammonia smell, and that's when we learned about the urea contamination. We settled with the aggregate supplier and assumed that the ammonia smell would dissipate with time. The owner proceeded to build the house on the foundation. The ammonia odor didn't dissipate, however, and the homeowner says the one-year-old home has even more of an odor problem than before. We tried coating the walls with a water-based acrylic sealer, but that only made the odor problem worse. Now the owner wants to be paid the cost of the house, since he says it's in an unlivable condition. Is there a solution to this problem?
For an 8-inch-thick wall drying from one side only, the ammonia vapor is likely to take months to years to dissipate. A nonbreatheable coating such as an epoxy might solve the problem, but you could have a problem getting the coating to bond properly to the wall. One consultant suggested that you buy the house, air out the basement for one or two years-- perhaps with forced ventilation--see if the odor goes away, then sell it. Another consultant, with tongue in cheek, suggested that during the two years, you could try renting the house to a person with a bad sinus condition. We'd welcome any suggestions for short-term solutions from our readers.